PHP not working in block

Hello, can anyone see why this would not be working in a block? When I run this code in an ad inserter block, the page displays very strange and I get a critical error message. I’m trying to open random videos in wp lightbox after clicking and image. No other info.

<?php
function displayRandomVideoWithBanner() {

    // Define video URLs and banner image URL
    $video_urls = array(
        "https://www.youtube.com/watch?v=VideoId1",
        "https://www.youtube.com/watch?v=VideoId2",
        "https://www.youtube.com/watch?v=VideoId3"
    );
    $banner_image_url = "https://website.com/wp-content/uploads/2023/07/banner-image.png";

    // Shuffle the video URLs
    shuffle($video_urls);

    // Select the first video URL
    $random_video_url = array_shift($video_urls);

    // Check if a valid video URL is available
    if ($random_video_url) {
        // Create HTML output
		echo "<a href='$random_video_url' rel='wp-video-lightbox'><img src='$banner_image_url' alt='alt text'></a>";
    } else {
        // If no valid video URL is available
        echo "Error: No valid videos found.";
    }
}

// Call to display the video and banner
displayRandomVideoWithBanner();
?>

I cant just use a simple [ADINSERTER ROTATE] because when I do, it doesn’t open the video in the wp lightbox, it just links directly to youtube.

Thank you